Unmanned underwater vehicles, such as torpedoes, can be deployed from submarines, aircraft, ships, or any similar deployment platform. Once deployed, the unmanned underwater vehicle is propelled towards a target. Historically, unmanned underwater vehicles have been propelled by many different power sources included liquid fuel (such as Otto Fuel) engines, electric motors and batteries, electric motors and fuel cells, chemically heated steam engines, compressed gas engines, and solid rocket motors.
Maximizing an effective range, while also maintaining a sprint speed (maximum high speed) capability, is one goal of unmanned underwater vehicle design, and is impacted by the type of power source utilized to achieve propulsion. The longer the unmanned underwater vehicle's range, the further the deployment platform can be from the target of the unmanned underwater vehicle, protecting the safety of the deployment platform. In addition to the range, a high sprint speed allows the unmanned underwater vehicle to overtake a moving target once the moving target has been alerted to the unmanned underwater vehicle's presence. As is appreciated in the art, most engine configurations trade off effective range for a higher sprint speed, or sprint speed for a higher effective range.